The present invention relates to power transmissions and in particular to those which are semi-automatic in nature and have epicylic planetary gear trains in combination with hydraulically activated power cylinder and clutch gearing controls as directed through a rotary distribution valve by means of straight line shifting control. The invention relates to combinations of achieving smooth gearing transitions through regulation, at idling speeds and at operating speeds, through a system of compensating fluid pressure versus spring compression resistance valves sensitive to main line pressure respectively. The invention further relates to an exclusive interconnected internal gear drive arrangement, of engine torque transference to a load shaft, through plural power paths, which employs a majority of die cast pinion gears.